Oh boy, that isn't exactly an easy budget to find anything decent in this day and age, especially since you want it to be YOM 2000 at the earliest!
If fuel economy and cheapness to run are your major criteria, then an Alto would probably be the best bet, but I'm not sure if there will be any auto ones in the price bracket.
If you want a more substantial car than an Alto that will still be ok to run then I would suggest looking at the K11 March, but finding a solid one might be a challenge. A slightly bigger option would be a Perodua Kelisa.
Another Nissan that is kicking around that general price is the AD Wagon, which will give you a load more space, and still not be too expensive to run. It's a bit basic though.
If Toyota is your thing, Solunas seem to be around that range, they are decent cars from what I know (basically a tercel with different front and rear, but they are looked down upon by the lankan baiyas because they were made in Thailand. Quite a few were around, so you might be able to find a decent one.
A left field option is a Ford Laser, it is almost entirely a Mazda 323/familia, but sells for less due to the badge. It will definitely be a nicer drive than most of the above, but ford specific body parts might be a challenge.
Keep in mind that all of these options are basically 20 years old by this point. Mechanical parts should be ok for a few years yet but body and trim bits will be getting scarce for everything but the Altos. Keep that in mind when looking.
Also, it is generally good practice to keep a reserve of about 200-300k for any repairs that the vehicle might need, it's usually best to get everything done in one go so you can use it without a hassle.
You sir, are completely misguided. Buying a vehicle based on maintaining it's resale value is retarded because you can never predict exactly what will happen in our market. Also, no matter what these broker idiots tell you, a well maintained car will always get a good price and a good buyer.
So instead of doing inane shi*t like you're doing now, pick a model you like, buy the best maintained example you can find (preferably one with full service history and a caring owner, not some dressed up, sale painted piece of shit with an altered mileage reading stupidly low) and then maintain that car in a proper manner and take care of it. If you need to sell, the buyers will come looking. Speaking from experience.
Supra_Natural's post in Best Used Car Under 1.6Mn was marked as the answer